Colorectal cancer will affect one in 20 individuals over the course of their lifetime. The ColoCare Study is a prospective cohort of men and women newly diagnosed with a first primary invasive colorectal cancer (stage I-IV) with repeat data and biospecimen collection beginning prior to surgery. The ColoCare Study was initiated at the Fred Hutchinson Cancer Research Center with subsequent consortium sites at the Moffitt Cancer Center, the German Cancer Research Center, and Huntsman Cancer Institute with institutional pilot/start-up funding to support patient recruitment. The goal of this study is to uniformly collet comprehensive sets of data and biospecimens from over 4000 multiethnic colorectal cancer patients at multiple time points (prior to surgery and 3, 6, 12, 24, 36, 48 and 60 months post-surgery), including detailed treatment and risk factor data, fresh and fixed tumor and normal tissue, visceral adipose tissue, blood, stool, urine, saliva, and quantitative accelerometry data t assess physical activity. Each ColoCare Study site leverages existing infrastructure, including access to electronic medical records and NCI comprehensive/designated cancer center cores, while utilizing well-established protocols for recruitment, data collection, and biospecimen ascertainment that are consistently applied across all sites. Patients are followed up both actively and passively by study staff (in-person and through medical record reviews), as well as via linkages to cancer registry and vital status records. Currently, using pilot/institutional fund at four existing sites, we have recruited >1100 patients (n=1010 baseline bloods). With this infrastructure grant, we propose 1) to extend the ColoCare consortium to two new study centers that will enrich our numbers of underrepresented minority participants (University of Southern California, LA, and Washington University School of Medicine, St. Louis) and 2) to continue and expand study procedures at all US sites, including energy balance assessments and molecular characterization of tumors. The support for expanded enrollment and continued follow-up of the ColoCare cohort will result in an estimated 4167 highly characterized enrollees. The repeat sampling of data and a diverse set of accompanying biospecimens at critical time points enables unprecedented epidemiologic and biomarker research that can inform clinical decision making and support evidence-based guidelines regarding lifestyle changes that impact outcomes. Additionally, we will establish an external advisory board and a community/participant advisory board to further guide infrastructure development and prioritize research use of this cohort. We will continue to participate in national and international consorti by contributing data and biospecimens. Support for this unique cohort of colorectal cancer patients will create a valuable resource for the broader research community. In-depth, repeated phenotyping within a single cohort will enable one-of-a-kind studies focused on the effects of health behaviors on prognosis, as well as the discovery of new biomarkers of clinically important outcomes.